The present invention relates to packaging and, more particularly, to packaging that allows sterilization of its contents with a subsequent high barrier to the ingress of oxygen and water vapor.
Many items, including, but not limited to, medical items such as drug-eluting stents, are required to be sterilized while in a package and, after sterilization, are required to be substantially isolated from oxygen and water vapor for prolonged time periods. To allow sterilization of an item in a package, the package may be formed from a breathable material that allows sterilizing gas to pass through the breathable material. These breathable materials include spun-bonded olefin products such as those sold by E.I. Du Pont de Nemours and Company (Wilmington, Del.) under the trademark TYVEK®. After sterilization and for the remainder of the life of the package, the breathable material provides a tortuous path for microbes, bacteria and other contaminants, allowing the package and its contents to remain sterile for a prolonged time period.
The breathable material, however, does not act as a barrier to the ingress of gases, including, but not limited to, oxygen, or water vapor. To provide a barrier, the packaging may be formed from a foil or other high-barrier material; however, high-barrier material does not allow sterilizing gas to pass through the material into the package.
Additionally, some packages require some type of scavenger to remove gases, moisture, etc. This scavenger cannot be exposed to sterilizing gas and must be added to the package after sterilization. As it is added after sterilization, the scavenger is not sterile and, therefore, must not have direct contact with the sterile contents.
U.S. Pat. No. 5,947,288 (Dykstra, et. al.) and U.S. Pat. No. 6,059,112 (Dykstra, et. al.) disclose a sterilizable pouch package with three layers wherein the inner layer has a perforation line and is of like length to, but narrower width than, the outer layers; the side edges of the inner layer are preferably unsealed in order to facilitate sterile presentation of the sterilized contents of the package.
U.S. Pat. No. 5,241,149 (Watanabe, et. al.) discloses a three-layer package in bag-form wherein an inner air-permeable film is sealed to the side edges of the package along with outer air-impermeable layers.
U.S. Patent Application 2005/0069452 (Varma, et. al.), PCT Application WO 2004/066876 (Clarke, et. al.) and Short-Term Irish Patent S83657 (Clark, et. al.) disclose a package for a drug-eluting stent. This package has two compartments separated by a breathable membrane internal wall wherein the side edges of the breathable membrane internal wall are included in the outer walls of the package.
PCT Application 2004/071308 (Duffy) discloses a three-layer pouch wherein the three layers are assembled and sealed together simultaneously by sandwiching an internal gas permeable microbe impermeable partition between two outer layers of material.
Prior art sterilizable packaging typically comprised a pouch with one foil layer and one TYVEK® layer, a thermoform tray insert in a foil pouch, or a thermoform tray with a TYVEK® lid in foil pouch. Such conventional packaging does not provide for regulation of ambient conditions such as circulation of air, exposure to oxygen or absorption of gases, moisture, etc. Without such regulation, the efficacy of the packaging and its contents may be compromised.
Accordingly, there is a need for a package that allows sterilization of its contents, provides for a separate area for a scavenger and minimizes the oxygen and water vapor transmission rates.